Lichens are a unique group of complex, flowerless plants growing on rocks and trees. There are thousands of kinds of lichens, which come in a wide variety of colors. The are composed of algae and fungi which unite to satisfy the needs of the lichens.5The autotrophic green algae produce all their own food through a process called photosynthesis and provide the lichen with nutritional elements. On the other hand, the heterotrophic fungus, which depends on other elements to provide its food, not only absorbs and stores water for 10 the plant, but also helps protect it. This union by which two dissimilar organisms live together is called "symbiosis."

This sharing enables lichens to resist the most adverse environmental conditions found on earth. They can be found in some very unlikely 15 places such as the polar ice caps as well as in tropical zone, in dry areas as well as in wet ones, on mountain peaks and along coastal areas.

The lichen's strong resistance to its hostile environment and its 20 ability to live in harmony with such environments is one example that humanity should consider in trying to solve its own problems.

1. Which of the following is not true?(A) Lichens are not simple plants.(B) The lichen habitat is limited to the polar ice caps.(C) Lichens can resist a hostile environment.(D) Heterotrophic plants depend on other elements to supply their food.2. What can be said about autotrophic plants and heterotrophic plants?(A) They produce their food in the same manner.(B) Heterotrophic plants produce all their own food.(C) Autotrophic plants need other elements to supply their food.(D) Their methods of food production are completely different.3. Which of the following conclusions could be made about lichens?(A) They are found worldwide and are complex plants made up of algae and fungi.(B) They are found worldwide and are simple plants, symbiotic in nature.(C) They are found worldwide and are compound plants made up entirely of algae.(D) Although found worldwide, lichens are found mostly as a simple plant form in the tropics.4. Which of the following directly relates to algae?(A) It offers protection to lichens.(B) It supplies water for lichens.(C) It supplies its own food.(D) It is dependent on other plants for its supply.